Elements in sheet or web form with a photopolymerizable layer on one side are known and used widely in the graphic arts. Upon imagewise exposure, the surface of the photopolymerized layer has different degrees of tackiness in exposed and unexposed areas. That latent image is developed with toner particles. An apparatus requiring feed and withdrawal rolls for moving an exposed element beneath a hopper and through associated processing stations has been disclosed in U.S. Pat. No. 4,069,791.